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[InstCombine] Check for isa<Instruction> before using cast<> 

Protects against casts from constexpr etc.

Reduced from oss-fuzz #4788 test case

llvm-svn: 321515
This commit is contained in:
Simon Pilgrim 2017-12-28 09:35:35 +00:00
parent 5a81bb73ad
commit 472689a159
2 changed files with 14 additions and 1 deletions
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2
llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
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@ -2376,7 +2376,7 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
// The compare intrinsic uses the above assumptions and therefore
// doesn't require additional flags.
if ((match(Arg0, m_OneUse(m_FSub(m_Value(A), m_Value(B)))) &&
match(Arg1, m_Zero()) &&
match(Arg1, m_Zero()) && isa<Instruction>(Arg0) &&
cast<Instruction>(Arg0)->getFastMathFlags().noInfs())) {
if (Arg0IsZero)
std::swap(A, B);

13
llvm/test/Transforms/InstCombine/X86/X86FsubCmpCombine.ll
View File

@ -122,6 +122,19 @@ entry:
}
define i8 @sub_compare_folding_swapPD256_undef(<4 x double> %a, <4 x double> %b) {
; CHECK-LABEL: @sub_compare_folding_swapPD256_undef(
; CHECK-NEXT: entry:
; CHECK-NEXT: [[TMP:%.*]] = tail call i8 @llvm.x86.avx512.mask.cmp.pd.256(<4 x double> fsub (<4 x double> undef, <4 x double> undef), <4 x double> zeroinitializer, i32 5, i8 -1)
; CHECK-NEXT: ret i8 [[TMP]]
;
entry:
%sub.i1 = fsub ninf <4 x double> undef, undef
%tmp = tail call i8 @llvm.x86.avx512.mask.cmp.pd.256(<4 x double> %sub.i1, <4 x double> zeroinitializer, i32 5, i8 -1)
ret i8 %tmp
}
define i8 @sub_compare_folding_swapPD512(<8 x double> %a, <8 x double> %b){
; CHECK-LABEL: @sub_compare_folding_swapPD512(
; CHECK-NEXT: entry: